1. Field of the Invention
The present invention relates to an electromagnetic miniature relay including at least one hermetically sealed contact unit with a change-over contact the movable contact of which consists of an elastic ferromagnetic diaphragm and the fixed contacts of which consist of contact poles of ferromagnetic material mounted within pole rings by hermetically sealing and magnetically and electrically insulating connections, the two pole rings and the diaphragm of a contact unit being connected with each other in a magnetically and electrically conducting manner and with the coil core of a drive coil in a magnetically conducting manner, the magnetic circuit being closed via outer elements.
2. Description of the Prior Art
Electromagnetic relays using diaphragm contacts as contact units are known and described in detail, for example, in Swiss Pat. No. 455 941. Contact units of this kind are especially known from Swiss Pat. No. 452 021 wherein several designs of diaphragms and contacts are described in view of their use of make, break or change-over contact. Further it is known to use permanent magnets for relays in order to achieve a magnetic adherence of the contacts after the removal of the control flux and/or to achieve a higher sensitivity of the relay. A magnetic latching relay of this kind is described e.g. in Swiss Pat. No. 498 482. In polarized relays for the reception of telegraphy signals permanent magnets were used for decades for improving the sensitivity.
Many of the above described relays of the prior art have the disadvantage that they cannot be mounted on printed circuit boards due to their size and almost all of these known relays have the disadvantage that they cannot be controlled directly by the low power output signals of conventional logic circuits. Further there are used basically different structures for different functions.